The Design of Metasurface Absorber Based on the Ring-shaped Resonator Lumped with Nonlinear Circuit for a Pulse Wave

The current design of the MetaSurface Absorber (MSA) has excellent absorption characteristics ofElectroMagnetic (EM) wave. However, the influence of incident EM wavefrom and power is rarely considered.In this paper, a nonlinear circuit based MSA is proposed, which can absorb selectively wave with specificwaveforms at the same frequency. The unit-cell structure of the proposed MSA is composed of a metal squarering resonator integrated with a nonlinear circuit of four diodes parallel with one resistor and capacitor, anintermediate dielectric substrate (Rogers4350) isolation layer and a bottom ground plane. The results show thatthe designed MSA can achieve an absorbance of 97% of the 50 ns short pulse at 3.2 GHz, while thecorresponding one of the continuous wave is only 21% at the same frequency. Around 3.2 GHz, the absorbanceof 50 ns pulse can be dynamically adjusted by changing incident pulse power, and the absorbance is always above 60%, while the corresponding one of the continuous wave is only fixed at about 20%. When the pulsewidth of the incident wave is increased, the absorption level of the designed MSA firstly increases and thendecreases significantly. In the case of oblique incident wave of TE and TM modes with 0 dBm power and -4dBm, the absorbance of the designed MSA is still more than 60%. Further research results show that theabsorption characteristics of the MSA is depend heavily on the design of capacitance as well as the geometricparameters of the unit-cell structure. This research has potential application prospects to wirelesscommunication, anti-EM interference, EM compatibility and other fields